High-temperature, structural disorder, phase transitions, and piezoelectric properties of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Ga</mml:mi><mml:mi mathvariant="normal">P</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>

Haines, J.; Cambon, O.; Prudhomme, Nathalie; Fraysse, G.; Keen, David A.; Chapon, L. C.; Tucker, Matthew G.

doi:10.1103/physrevb.73.014103

Cited by 53 publications

(51 citation statements)

References 41 publications

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“…Thus, the CoS structure remains when more (Na atoms) and more (O atoms) atoms are added into the structure. Interestingly, when this compound is heated, the high-temperature phase -NaCoPO 4 adopts a structure that has been related to a stuffed tridymite structure (Hammond & Barbier, 1996), in which the CoP subarray forms a four-connected net characteristic of (IV)-(IV) compounds. Again, such types of transformations, as discussed in the article, are precisely those often observed in binary compounds.…”

Section: Discussionmentioning

confidence: 99%

“…Let us recall that the P6 3 /mmc structure of Na 2 SO 4 is stable (with disorder at 520 K) at lower temperatures (450 K below) than ZnSO 4 . In the case of the related compound GaPO 4 (Haines et al, 2006) thermal disorder is induced at 1303 K with the O-atom density forming a continuous ring around the vector joining neighbouring Ga and P atoms. This type of disorder, however, is closer to the image of fixed O atoms near the bond pairs than the rotational disorder observed in both high-temperature phases of Na 2 SO 4 and Li 2 SO 4 .…”

Section: The Phases Of Na 2 S and Their Related Oxidesmentioning

confidence: 99%

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Pseudoatoms and preferred skeletons in crystals

Vegas

García-Baonza

2007

Acta Crystallogr Sect B

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The generalization of the Zintl–Klemm concept provides a universal formulation of a crystal structure in terms of universal building skeletons formed by Klemm's pseudoatoms: atoms that behave structurally according to their formal total electron charge. An important difference in this novel view is that charge is considered to be transferred, in the strict Zintl's sense, from the donor cations to the building skeleton as a whole, not specifically to a given atom or ion. Although application is restricted to (IV)–(IV) compounds (group 14 structures), the principle seems to be universal and can be applied to understand, to relate and to predict the structure of complex compounds on the basis of more simple structures, e.g. a given AB skeleton provides the building block for A 2 B, AB 2, ABX m etc. compounds of a very different nature. The application of such a principle only requires information on the constituent atoms and on the existing phases of the p-block elements (observed under ambient and high-pressure and/or high-temperature conditions). The ideas introduced here demonstrate, for the first time, that a generalization of the Zintl–Klemm concept is possible and that such a generalization helps to establish a univocal link between chemical composition (in terms of pseudoatoms) and the crystalline structures observed experimentally.

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Section: Discussionmentioning

confidence: 99%

Section: The Phases Of Na 2 S and Their Related Oxidesmentioning

confidence: 99%

Pseudoatoms and preferred skeletons in crystals

Vegas

García-Baonza

2007

Acta Crystallogr Sect B

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“…In addition, the well-known α-β phase transition, which appears around 573 °C in α-SiO 2 (θ = 144.2°) [19,26] does not occur when the tilt angle δ is over 22° (leading to θ under 136°) [9,13,14,22,25]. In other words, the transition from an α phase to a β phase is absent for α-GeO 2 and α-GaPO 4 crystallized materials (θ = 130.04° and θ = 134.60°, respectively) [13,14,17,22,28,29].…”

Section: Introductionmentioning

confidence: 98%

“…In the XO 2 (X = Si, Ge) and MPO 4 (M = Fe, Al, Ga, B) family, the α-quartz-like structure is composed of either only XO 4 corner-shared tetrahedra or of both MO 4 and PO 4 tetrahedra forming a trigonal system [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The α-phase (P3 1 21 or P3 2 21, respectively left-handed or right-handed, Z = 3) is derived from the β-phase (P6 2 22 or P6 4 22) by a symmetry loss induced by a tilt of the tetrahedra around the b-axis.…”

Section: Introductionmentioning

confidence: 99%

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Flux-Grown Piezoelectric Materials: Application to α-Quartz Analogues

et al. 2014

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Using the slow-cooling method in selected MoO 3 -based fluxes, single-crystals of GeO 2 and GaPO 4 materials with an α-quartz-like structure were grown at high temperatures (T ≥ 950 °C). These piezoelectric materials were obtained in millimeter-size as well-faceted, visually colorless and transparent crystals. Compared to crystals grown by hydrothermal methods, infrared and Raman measurements revealed flux-grown samples without significant hydroxyl group contamination and thermal analyses demonstrated a total reversibility of the α-quartz ↔ β-cristobalite phase transition for GaPO 4 and an absence of phase transition before melting for α-GeO 2 . The elastic constants C IJ (with I, J indices from 1 to 6) of these flux-grown piezoelectric crystals were experimentally determined at room and high temperatures. The ambient results for as-grown α-GaPO 4 were in good agreement with those obtained from hydrothermally-grown samples and the two longitudinal elastic constants measured versus temperature up to 850 °C showed a monotonous evolution. The extraction of the ambient piezoelectric stress contribution e 11 from the C D 11 to C E 11 difference gave for the piezoelectric strain coefficient d 11 of flux-grown α-GeO 2 crystal a value of 5.7(2) pC/N, which is more than twice that of α-quartz. As the α-quartz structure of GeO 2 remained stable up to melting, a piezoelectric activity was observed up to 1000 °C.

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Acoustic Loss in LiNb_1−xTa_xO₃at Temperatures up to 900 °C

Yakhnevych,

Sargsyan,

El Azzouzi

et al. 2024

Physica Status Solidi (a)

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Lithium niobate‐lithium tantalate solid solutions are new piezoelectric crystals that enable to combine the advantages of their edge compounds with respect to the high thermal stability of lithium tantalate and the high Curie temperature of lithium niobate. This study aims to determine of the acoustic losses of bulk resonators with varying Nb/Ta ratios and their correlation with charge transport at temperatures up to 900 °C and at reduced oxygen partial pressures. Techniques such as resonant piezoelectric spectroscopy and contactless resonant ringdown spectroscopy are used to determine the acoustic losses. Further, the electrical conductivity is determined by impedance spectroscopy. A one‐dimensional physical model for vibrating plates is fitted to the data to extract key parameters such as piezoelectric coefficients and elastic modulus as a function of temperature. Noncontacting determination of loss excludes the impact of metal electrodes and reveals up to 300 °C values in the order of Akhiezer‐type losses. Resonators operated at 2 MHz show a rapid loss increase above about 450 °C, which is attributed to the piezoelectric/carrier relaxation. The latter follows from atomistic models using the key parameters mentioned and the electrical conductivity. The modeling includes variation of the resonance frequency and suggests higher resonance frequencies to lower the acoustic loss.

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High-temperature, structural disorder, phase transitions, and piezoelectric properties ofGaPO4

Cited by 53 publications

References 41 publications

Pseudoatoms and preferred skeletons in crystals

Pseudoatoms and preferred skeletons in crystals

Flux-Grown Piezoelectric Materials: Application to α-Quartz Analogues

Acoustic Loss in LiNb_1−xTa_xO₃at Temperatures up to 900 °C

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High-temperature, structural disorder, phase transitions, and piezoelectric properties ofGaPO4

Cited by 53 publications

References 41 publications

Pseudoatoms and preferred skeletons in crystals

Pseudoatoms and preferred skeletons in crystals

Flux-Grown Piezoelectric Materials: Application to α-Quartz Analogues

Acoustic Loss in LiNb1−xTaxO3at Temperatures up to 900 °C

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Acoustic Loss in LiNb_1−xTa_xO₃at Temperatures up to 900 °C